<template>
  <div class="home-page">
    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">
        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li class="nav-item" v-if="user">
                <nuxt-link 
                  class="nav-link" 
                  :class="{
                    active: tab === 'your_feed'
                  }"
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'your_feed'
                    }
                  }"
                  exact
                >Your Feed</nuxt-link>
              </li>
              <li class="nav-item">
                <nuxt-link 
                  class="nav-link"
                  :class="{
                    active: tab === 'global_feed'
                  }"
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'global_feed'
                    }
                  }"
                  exact
                >Global Feed</nuxt-link>
              </li>
              <li class="nav-item" v-if="tag">
                <nuxt-link
                  class="nav-link"
                  :class="{
                    active: tab === 'tag'
                  }"
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'tag',
                      tag: tag
                    }
                  }"
                >#{{ tag }}</nuxt-link>
              </li>
            </ul>
          </div>

          <div class="article-preview" v-for="article in articles" :key="article.slug">
            <div class="article-meta">
              <nuxt-link :to="{
                name: 'profile',
                params: {
                  username: article.author.username
                }
              }"><img :src="article.author.image" /></nuxt-link>
              <div class="info">
                <!-- <a href="" class="author">Eric Simons</a> -->
                <nuxt-link class="author" :to="{
                name: 'profile',
                params: {
                  username: article.author.username
                }
              }">{{ article.author.username }}
                </nuxt-link>
                <span class="date">{{ article.createdAt | date }}</span>
              </div>
              <button 
                class="btn btn-outline-primary btn-sm pull-xs-right"
                :class="{
                  active: article.favorited
                }"
                @click="onFavorite(article)"
                :disabled="article.favorDisabled"
              >
                <i class="ion-heart"></i> {{ article.favoritesCount }}
              </button>
            </div>
            <nuxt-link :to="{
              name: 'article',
              params: {
                id: article.slug
              }
            }" class="preview-link">
              <h1>{{ article.title }}</h1>
              <p>{{ article.description
                 }}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>

          <!-- 分页列表 -->
          <ul class="pagination">
            <li :class="{ 'page-item': true, active: item === page }" v-for="item in totalPage" :key="item">
              <nuxt-link class="page-link" :to="{
                  name: 'home',
                  query: {
                    page: item,
                    tag: $route.query.tag,
                    tab: tab
                  }
                }">{{ item }}</nuxt-link>
            </li>
          </ul>
          <!-- /分页列表 -->

        </div>

        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>

            <div class="tag-list">
              <nuxt-link 
                :to="{
                  name: 'home',
                  query: {
                    tag: item,
                    tab: 'tag'
                  }
                }"
                class="tag-pill tag-default" v-for="item in tags" :key="item">
                {{ item }}
              </nuxt-link>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import { getArticles, getFeedArticles, addFavorite, cancelFavorite } from '@/api/article'
import { getTags } from '@/api/tag'
import { mapState } from 'vuex' 
export default {
  name: "HomeIndex",
  watchQuery: ['page', 'tag', 'tab'],
  async asyncData ({ query, store }) {
    const page = Number.parseInt(query.page || 1)
    const limit = 20
    // const { data } = await getArticles({
    //   limit,
    //   offset: (page - 1) * limit,
    // })
    // const { data: tagData } = await getTags()

    const { tag } = query
    const tab = query.tab || 'global_feed'
    const getArticlesApi = store.state.user && tab === 'your_feed' ? getFeedArticles : getArticles
    // 两个异步任务没有关联关系，所以改为并行执行节省时间
    // Promise.all返回执行的所有异步任务结果组成的数组
    const [ articleRes, tagRes ] = await Promise.all([
      getArticlesApi({
        limit,
        offset: (page - 1) * limit,
        tag: query.tag
      }),
      getTags ()
    ])
    const { articles, articlesCount } = articleRes.data
    const { tags } = tagRes.data

    // 增加文章的禁用状态
    articles.forEach(article => article.favorDisabled = false)

    return {
      articles: articles,
      articlesCount: articlesCount,
      limit,
      page,
      tags,
      tag,
      tab: query.tab || 'global_feed'
    }
  },
  computed: {
    ...mapState(['user']),
    totalPage () {
      return Math.ceil(this.articlesCount / this.limit)
    }
  },
  methods: {
    async onFavorite (article) {
      article.favorDisabled = true
      if (article.favorited) {
        await cancelFavorite(article.slug)
        article.favorited = false
        article.favoritesCount -= 1
      } else {
        await addFavorite(article.slug)
        article.favorited = true
        article.favoritesCount += 1
      }
      article.favorDisabled = false
    }
  }
};
</script>

<style>
</style>